I have perl scripts which were running in Windows 7 just fine as of this morning. I made the mistake of using NotePad as the default for opening/editng my .pl files. Now,
I have the same problem. None of the method mentioned above solve the problem. The problem actually came from Windows 7! Windows 7 Doesn't allow you to associate .pl to perl.exe in c:\Perl64 directory, for whatever reason. Here is the solution: If you look at c:\Perl64\Bin directory (or the path where your ActivePerl binary installed), you'll see another file: Perl5.14.2.exe. This is the same file as perl.exe in same directory but with version number attached as postfix in the name. You can associate .pl file to that Perl5.14.2.exe instead of perl.exe. Bingo, it works now.